The skin is cleansed and a prep solution will be applied to remove surface oils and allow the peel to penetrate the skin evenly. Any sensitive areas that cannot be treated will be protected with a thin film of petroleum jelly. Your eyes will be covered to protect them. One or more chemical mixtures will be applied, such as glycolic acid (from sugar cane), trichloroacetic acid (similar to bleach), salicylic acid (wintergreen—good for acne), lactic acid (from milk), or a combination peel called a Jessners peel. The peel will be applied in 1–3 layers, depending on the depth of penetration intended. The acids react with the skin to produce a “controlled wound,” allowing fresh skin to regenerate and emerge. A tingling, burning or hot sensation is normal. Most peels remain on the skin only a few minutes, and are closely watched by the esthetician. A fan may help you stay more comfortable. After some peels, a neutralizing solution is applied to stop the peel. Other peels are self-timed and stop on their own.